ESR of Metal polypropylene capacitors at -25degC?

[cupoftea]

Hi,
Do you know the esr of this metal polypropylene capacitor (or any) at -25degc.

https://www.tdk-electronics.tdk.com/inf/20/20/ds/MKP_B32774P_778P.pdf

We are interested in a 47uF, 630VDC MetPoly, but any info on how ESR is at low temps for met poly much appreciated. Google and App notes dont say as per search.

 

[Easy peasy]

D'oh - there is no 47uF 630VDC in that data sheet

as to ESR it will be the same as the min Z for, for example, the 50uF 630V part, but actually a little lower at -25 deg C

 

[FvM]

Polypropylene cap ESR is mainly metal (aluminium) resistance, positive TK ~K.

 

[Easy peasy]

actually the end caps are nearly pure zinc spray ( one of the few things that adheres to aluminium ) - the zinc also allows soldering in a low O2 environment - to the eventual pins - the Al sputtering of the plastic foil ( polyprop ) is surprisingly thin - but as it is metal - yes it's temp-Co of resistance is positive - hence lower R as the temp falls.
Too much hot/cold cycling can bugger up the connection of the zinc spray to the foils - this is remedied ever so slightly by clever potting compounds that shrink a bit when cured and force the end caps ( zinc ) against the foils.